The present invention relates to a security method for a security system of a vehicle according to the preamble of the independent method claim. Furthermore, the invention relates to a security system according to the preamble of the independent device claim.
It is known from the prior art that a portable access device, for example a smartphone or an ID transmitter, can be used to activate a security-related function in a vehicle. One such function is, for example, granting access to the vehicle or authorizing engine start. For this purpose, a security system of the vehicle can be provided which, for example, performs and/or evaluates data transfer between the vehicle and the access device. By evaluating the data transfer, for example, a distance of the access device to the vehicle can be measured and/or an approach of the access device can be detected. For example, an activation of the security-related function can only occur when the access device is in the vicinity of the vehicle. This allows, for example, to provide a passive access system (keyless entry system).
Conventional security systems use a “connection-based data transfer” to ensure the security when activating the function. Exemplarily, an authentication can then occur at the connection establishment. In this case, however, the disadvantage has been found that such a data transfer, in particular the connection establishment, can only be performed in a consuming, inflexible and complicated way. Possibly, it may also be a technical challenge to sufficiently limit disconnections and/or connection failures in the case of data transfer involving connections.
In principle, a “connectionless communication” can also be used for data transfer. However, the use of a connectionless data transfer has the disadvantage that the transmitted data packets are not automatically sufficiently protected against manipulation and are usually addressed to all. In other words, the integrity of the transmitted data may not be sufficiently secured or technically complex to ensure. In the case of passive security systems, in particular access systems which use the reception power at the data transfer as an indication of the approach of an access device, this can lead to the wrong device being detected for a distance measurement.